1. Field of the Invention
This invention relates generally to printing on non-planar surfaces and, more specifically, to Methods and Apparatus for Image Transfer to Multiple Articles Having Non-planar Surfaces.
2. Description of Related Art
Various types of image transfer techniques have been suggested in the past for imprinting images on a number of different material surfaces including cloth, wood, metal and ceramics. A very common technique, which has been widely used, is silk screening. The problem with silk screening is that it is generally limited to printing on smooth, flat surfaces. Furthermore, even on flat surfaces, the silk screening process produces a relatively low quality print when compared to that produced by lithography, gravure, letterpress sublimation and laser printing.
For imaging on metal surfaces, sublimation techniques are often used. An example of the prior sublimation processes can be found in Blake, U.S. Pat. No. 3,484,342 issued Dec. 16, 1969 and Fromson et al, U.S. Pat. No. 4,201,821 issued May 6, 1980; both Blake and Fromson suggest decorating unsealed and uncoated anodized aluminum using sublimation techniques. Sublimation processes, like screen printing, also suffer from being limited to flat, smooth surfaces. Transferring an image or graphic to a sphere or curved, cylindrically tapered surface by sublimation is extremely difficult, and such an approach, if achievable at all, would typically result in a poor quality, highly distorted image.
When printing on non-planar surfaces has been required, several techniques have been suggested. An example process is that disclosed by Stirbis et al, U.S. Pat. No. 4,941,266; the Stirbis apparatus (for decorating a cylindrical can) makes use of a multiple station ink supply and transfer apparatus for transferring ink from an in fountain to a rotatable inking blanket wheel through a plate cylinder. The Stirbis apparatus further includes an ink image registration adjustment apparatus and an axial and circumferential tightness control apparatus operatively associated with each plate cylinder and each ink supply and transfer apparatus. There have been additional prior techniques suggested for imprinting images on non-planar surfaces (including electro photographic imaging and magnetic imaging), but these techniques have met with limited commercial success.
Another prior system, Carlson, U.S. Pat. No. 5,831,641 discloses a method and apparatus for imprinting images on non-planar surfaces, including the surfaces of various types of three-dimensional articles, such as baseball bats. The Carlson apparatus includes a modified ink jet plotter coupled with an article positioning apparatus which functions to automatically maintain the surface of the article to be printed within a plane substantially parallel to and slightly spaced apart from the place within which the ink jet nozzles of the ink jet plotter reside.
Another prior art technique, which is frequently used to decorate surfaces, such as those from anodized aluminum, involves the use of transfer films. These films typically overlay the metal surface and undesirably, are subject to film deterioration and unattractive abrasion. A very popular prior art printing technique, which has found wide acceptance in recent years, is ink jet printing. Within the past several years, this technology has become the dominant technology for printing color images and graphics in the office and home markets. Ink jet printing basically involves a process whereby ink particles are projected in a continuous stream toward the surface to be imprinted using appropriate computer control to create text and graphics on the printing substrate. A number of different types of ink jet printers/plotters are readily commercially available from sources such as Calcomp, Packard Bell, NEC Technologies and Mutoh America, Inc.
As will be better understood from the discussion which follows, the method and apparatus of the present invention overcomes most of the problems encountered in prior art attempts to print high quality, detailed images on non-planar surfaces by employing a uniquely modified prior art ink jet image transfer technique.